1. Field of the Invention
The present invention relates to a method for producing bicyclic guanidines.
2. Background Information
Bicyclic guanidines, such as 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), are chemically active and, therefore, can be used to catalyze a variety of chemical reactions. An important consideration in the commercial exploitation of bicyclic guanidines as a catalyst (for any reaction) is that bicyclic guanidines be relatively inexpensive to purchase or easily produced. Published methods for synthesizing bicyclic guanidines, however, are often complicated, often involve the use of a multiple step synthesis process, and/or require the use of prohibitively expensive starting materials which may be hazardous in a variety of ways.
For example, some methods utilize carbon disulfide (CS2) in the production of bicyclic guanidines. However, there are regulatory and handling issues associated with the use of carbon disulfide. For instance, air transport of carbon disulfide is typically prohibited. Additionally, contact with carbon disulfide with air should be avoided because the combination of high volatility, wide flammability range, and low ignition temperature results in a readily combustible mixture.
Accordingly, there is a need for a process for producing bicyclic guanidines at relatively high yields while not using hazardous materials, such as carbon disulfide, as an ingredient to produce the bicyclic guanidines.